Method of making pigment dispersion containing a carrier such as castor oil or vegetable wax

Abstract

A process of dispersing at least one pigment into a carrier such as castor oil or a vegetable wax such as palm oil glyceride wax. The resulting dispersion exhibits excellent color development and is fluid at room temperature. Suitable pigments include FD&C, D&C and inorganic pigments.

1. A process for preparing a dispersion, which comprises
 (i) premixing a pigment by means of a high shear mixer selected from the group consisting of a Cowles dissolver, a single blade mixer, a Banbury mill, and a Gaullin homogenizer with a carrier selected from the group consisting of castor oil and a vegetable wax to produce a mixture; and 
 (ii) effectively mixing the mixture by means of a bead mill for a time sufficient to uniformly disperse said pigment in said carrier to produce a dispersion having a particle size distribution. 
 
     
     
       2. The process of  claim 1 , in which said mixing step (ii) is performed at 60 to 101° F. 
     
     
       3. The process of  claim 2 , in which said mixing step (ii) is performed at 75 to 95° F. 
     
     
       4. The process of  claim 1 , wherein said pigment is at least one member of the group consisting of Black Iron Oxide, Red Iron Oxide, Yellow Iron Oxide, D&C Red No. 7, FD&C Yellow No. 5, FD&C Yellow No. 6, and mixtures thereof. 
     
     
       5. The process of  claim 1 , wherein said mixing step (ii) employs at least one member at the group consisting of steel, glass and zirconium shot. 
     
     
       6. The process of  claim 1 , wherein said carrier is castor oil. 
     
     
       7. The process of  claim 1 , wherein said carrier is a vegetable wax. 
     
     
       8. The process of  claim 7 , wherein said vegetable wax comprises palm oil glyceride wax. 
     
     
       9. A pigment dispersion produced by the process of  claim 1 , having a viscosity of from 2,000 to 5,500 cps and a particle size distribution.